1/* ====================================================================
2 * Copyright (c) 2008 The OpenSSL Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in
13 * the documentation and/or other materials provided with the
14 * distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 * software must display the following acknowledgment:
18 * "This product includes software developed by the OpenSSL Project
19 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 * endorse or promote products derived from this software without
23 * prior written permission. For written permission, please contact
24 * openssl-core@openssl.org.
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 * nor may "OpenSSL" appear in their names without prior written
28 * permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 * acknowledgment:
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ==================================================================== */
48
49#include <openssl/type_check.h>
50
51#include <assert.h>
52#include <string.h>
53
54#include "internal.h"
55
56
57OPENSSL_STATIC_ASSERT(16 % sizeof(size_t) == 0,
58 "block cannot be divided into size_t");
59
60void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
61 const AES_KEY *key, uint8_t ivec[16], unsigned *num,
62 int enc, block128_f block) {
63 assert(in && out && key && ivec && num);
64
65 unsigned n = *num;
66
67 if (enc) {
68 while (n && len) {
69 *(out++) = ivec[n] ^= *(in++);
70 --len;
71 n = (n + 1) % 16;
72 }
73 while (len >= 16) {
74 (*block)(ivec, ivec, key);
75 for (; n < 16; n += sizeof(size_t)) {
76 size_t tmp = load_word_le(ivec + n) ^ load_word_le(in + n);
77 store_word_le(ivec + n, tmp);
78 store_word_le(out + n, tmp);
79 }
80 len -= 16;
81 out += 16;
82 in += 16;
83 n = 0;
84 }
85 if (len) {
86 (*block)(ivec, ivec, key);
87 while (len--) {
88 out[n] = ivec[n] ^= in[n];
89 ++n;
90 }
91 }
92 *num = n;
93 return;
94 } else {
95 while (n && len) {
96 uint8_t c;
97 *(out++) = ivec[n] ^ (c = *(in++));
98 ivec[n] = c;
99 --len;
100 n = (n + 1) % 16;
101 }
102 while (len >= 16) {
103 (*block)(ivec, ivec, key);
104 for (; n < 16; n += sizeof(size_t)) {
105 size_t t = load_word_le(in + n);
106 store_word_le(out + n, load_word_le(ivec + n) ^ t);
107 store_word_le(ivec + n, t);
108 }
109 len -= 16;
110 out += 16;
111 in += 16;
112 n = 0;
113 }
114 if (len) {
115 (*block)(ivec, ivec, key);
116 while (len--) {
117 uint8_t c;
118 out[n] = ivec[n] ^ (c = in[n]);
119 ivec[n] = c;
120 ++n;
121 }
122 }
123 *num = n;
124 return;
125 }
126}
127
128
129/* This expects a single block of size nbits for both in and out. Note that
130 it corrupts any extra bits in the last byte of out */
131static void cfbr_encrypt_block(const uint8_t *in, uint8_t *out, unsigned nbits,
132 const AES_KEY *key, uint8_t ivec[16], int enc,
133 block128_f block) {
134 int n, rem, num;
135 uint8_t ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't use) one
136 byte off the end */
137
138 if (nbits <= 0 || nbits > 128) {
139 return;
140 }
141
142 // fill in the first half of the new IV with the current IV
143 OPENSSL_memcpy(ovec, ivec, 16);
144 // construct the new IV
145 (*block)(ivec, ivec, key);
146 num = (nbits + 7) / 8;
147 if (enc) {
148 // encrypt the input
149 for (n = 0; n < num; ++n) {
150 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]);
151 }
152 } else {
153 // decrypt the input
154 for (n = 0; n < num; ++n) {
155 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n];
156 }
157 }
158 // shift ovec left...
159 rem = nbits % 8;
160 num = nbits / 8;
161 if (rem == 0) {
162 OPENSSL_memcpy(ivec, ovec + num, 16);
163 } else {
164 for (n = 0; n < 16; ++n) {
165 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
166 }
167 }
168
169 // it is not necessary to cleanse ovec, since the IV is not secret
170}
171
172// N.B. This expects the input to be packed, MS bit first
173void CRYPTO_cfb128_1_encrypt(const uint8_t *in, uint8_t *out, size_t bits,
174 const AES_KEY *key, uint8_t ivec[16],
175 unsigned *num, int enc, block128_f block) {
176 size_t n;
177 uint8_t c[1], d[1];
178
179 assert(in && out && key && ivec && num);
180 assert(*num == 0);
181
182 for (n = 0; n < bits; ++n) {
183 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
184 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block);
185 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) |
186 ((d[0] & 0x80) >> (unsigned int)(n % 8));
187 }
188}
189
190void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
191 size_t length, const AES_KEY *key,
192 unsigned char ivec[16], unsigned *num, int enc,
193 block128_f block) {
194 size_t n;
195
196 assert(in && out && key && ivec && num);
197 assert(*num == 0);
198
199 for (n = 0; n < length; ++n) {
200 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block);
201 }
202}
203